The present invention, in some embodiments thereof, relates to a method of receiving and transmitting Quadrature Amplitude Modulated (QAM) transmissions.
In many communication applications a receiver makes a decision about a transmitted symbol based on a corresponding received symbol. A component responsible for making such decisions is termed here “slicer” since it slices the symbol space into regions. Each region of symbol space corresponds to a different constellation symbol. In linear modulations such as Pulse Amplitude Modulation (PAM), QAM and Phase Shift keying (PSK) decisions are usually based on a predefined grid.
Reference is now made to FIG. 1, which is a simplified graph 100 demonstrating a standard slicer grid 104 for a 64 QAM constellation with symbols 103 embedded in Additive White Gaussian Noise (AWGN).
A slicer based on the standard slicer grid 104 is termed herein a standard slicer.
The graph 100 of FIG. 1 has a I axis 101 and an Q axis 102, and depicts the symbols 103 received by a receiver, where the symbols 103 are embedded in AWGN, and therefore are not sharply-defined points at centers of grid 104 cells, but are rather spread out within the grid 104 cells. The grid 104 cell lines designate standard slicing region boundaries.
Additional Background Art Includes:
An article titled “1024-QAM Demodulator Robust to Phase Noise of Cable STB Tuners” by Takuya Kurakake, Naoyoshi Nakamura, and Kimiyuki Oyamada, published in IEEE Transactions on Consumer 418 Electronics, Vol. 51, No. 2, May 2005, pages 413-418.
An article titled “Efficient Modulation for Band-Limited Channels” by G. David Forney, Jr., Robert G. Gallager, Gordon R. Lang, Fred M. Longstaff and Shahid U. Qureshi, published in IEEE Journal On Selected Areas In Communications, Vol. Sac-2, No. 5, September 1984, Pages 632-647.
An article titled “High Order Modulation Shaped To Work With Radio Imperfections” by Karl Martin Gjertsen, of Nera Networks AS, P.O. Box 7090, N-5020 Bergen, Norway, published in ARMMS RF & Microwave Society conference, 2005.
An article titled “Performance of Nonuniform Constellations on the Gaussian Channel” by W. Betts, A. R. Calderbank, and Rajiv Laroia, published in IEEE Transactions On Information Theory, Vol. 40, No. 5, September 1994, pages 1633-1638.
An article titled “Performance Optimization of High Order QAM in Presence of Phase Noise and AWGN: Application to a Decision Directed Frequency Synchronization System” by Stephane Bougeard, Jean-Francois Helard and Isabelle Siaud, published in Wireless Personal Communications (2006) 37: 123-138, Springer 2006.
The disclosures of all references mentioned above and throughout the present specification, as well as the disclosures of all references mentioned in those references, are hereby incorporated herein by reference.